Method for storing silica-based material, package produced with the method and use of package for packaging of silica-based products

Abstract

A method for storing a water-soluble undissolved silica-based material, optionally with an incorporated functional agent. The method includes immersing the material in an aqueous liquid phase which is initially saturated with a water-soluble silica-based material which is the same or different than the undissolved silica-based material, such that the undissolved silica-based material does not essentially dissolve into the liquid phase during storage, or the proportion of the amount of the initially undissolved silica-based material to the amount of the liquid phase is such that the liquid phase will be saturated or essentially saturated by a dissolved portion of the water-soluble undissolved silica-based material during storage, which dissolved portion of said water soluble undissolved silica-based material is less than 20%. Also disclosed is a storage package which may preferably be used to store functional agents, delivery devices or implants.

The invention claimed is: 
     
       1. A method for storage of an implant or delivery device, comprising the steps of:
 i.) providing an implant or delivery device, said implant or delivery device comprising a water-soluble, undissolved silica-based material consisting of SiO 2  and/or hydrolysed SiO 2 , said water-soluble, undissolved silica-based material comprising at least 50% of dry matter calculated as silicon dioxide (SiO 2 ), said water-soluble undissolved silica-based material further comprising a functional agent incorporated therein; 
 ii.) immersing said implant or delivery device in a liquid phase comprising water, such that 
 a) said liquid phase is saturated with a water-soluble silica-based material, which is the same or different than said water-soluble, undissolved silica-based material, wherein said water-soluble, undissolved silica-based material does not at all or does not essentially dissolve into said liquid phase during storage, or 
 b) an amount of said water-soluble, undissolved silica-based material is dissolved into said liquid phase, thereby saturating the liquid phase, with the proviso that the dissolved amount of said water-soluble silica-based material is less than 20% of an initial amount of said water-soluble, undissolved silica-based material; and 
 iii.) storing said implant or delivery device in said liquid phase for at least three months, 
 wherein said functional agent is a biologically active agent selected from the group consisting of viruses, a living micro-organism or a spore thereof, living animal cells, living plant cells and a nucleic acid. 
 
     
     
       2. The storage method of  claim 1 , further comprising the step of:
 dissolving said water-soluble, undissolved silica-based material resulting in release of said functional agent. 
 
     
     
       3. The storage method of  claim 1 , wherein the liquid phase is saturated or essentially saturated with Si(OH) 4 . 
     
     
       4. The storage method of  claim 1 , wherein the liquid phase comprises at least 1% water. 
     
     
       5. The storage method of  claim 1 , wherein the pH of the liquid phase is <9. 
     
     
       6. The method of  claim 1 , wherein said water soluble, undissolved silica-based material is sol-gel derived. 
     
     
       7. The storage method of  claim 1 , wherein the sol-gel derived material is immersed in said liquid phase only after the sol-gel derived has been aged and/or dried such that the weight of the sol-gel derived is ≦90% of the weight of sol wherefrom the material was derived. 
     
     
       8. The storage method of  claim 1 , wherein a desired property of the undissolved silica-based material is preserved during storage. 
     
     
       9. The storage method of  claim 1 , wherein said living micro-organism or a spore thereof is selected from the group consisting of bacteria, protozoa and fungi. 
     
     
       10. A package containing an implant or delivery device, said package comprising:
 i.) an essentially closed housing enclosing an implant or delivery device immersed within a liquid phase comprising water, wherein 
 a) said implant or delivery device comprises a water-soluble, undissolved silica-based material prepared from an alkoxide and of which at least 50%, calculated as silicon dioxide (SiO 2 ) of dry matter, comprises SiO 2  and/or hydrolysed SiO 2 , with a functional agent incorporated therein; 
 b) said liquid phase is saturated with a water-soluble silica-based material, which is the same or different than said water-soluble, undissolved silica-based material, such that said water-soluble, undissolved silica-based material does not at all or does not essentially dissolve into said liquid phase during storage, or an amount of said water-soluble, undissolved silica-based material is dissolved into said liquid phase, thereby saturating the liquid phase, with the proviso that the dissolved amount of said water-soluble silica-based material is less than 20% of an initial amount of said water-soluble, undissolved silica-based material; 
 and wherein the functional agent is a biologically active agent selected from the group consisting of viruses, a living micro-organism or a spore thereof, living animal cells, living plant cells and a nucleic acid. 
 
     
     
       11. The package of  claim 10 , wherein the liquid phase comprises more than 20 ppm of Si calculated as SiO 2 . 
     
     
       12. The package of  claim 10 , wherein said micro-organism is selected from the group consisting of bacteria, protozoa and fungi. 
     
     
       13. The package of  claim 10 , wherein said functional agent is a nucleic acid. 
     
     
       14. The package of  claim 10 , wherein said delivery device is adapted for oral, buccal, rectal, parenteral, pulmonary, nasal, ocular, intrauterine, vaginal, urethral, topical or transdermal drug delivery. 
     
     
       15. The package of  claim 10 , wherein said implant is a member of the group consisting of a medical device, a tissue engineering scaffold, a prosthesis and an injectable device.